Rob Lowe gets candid with ET's Jann Carl on the set of "Brothers & Sisters."

ET's JANN CARL was on the set of "Brothers & Sisters" for the interview that everyone wants -- and only ET has: ROB LOWE speaking for the first time about the former nanny who is alleging that he sexually harassed her.

"We live in a time where anybody can say anything about anybody," Rob tells Jann. "You want to defend your family! Now it's in the court system and potentially a criminal investigation."

The "Brothers and Sisters" star goes on to explain that he and his family have been the recipients of a great deal of well wishes, saying, "The support has been fantastic and really, really humbling."

Rob and wife SHERYL BERKOFF have two children -- EDWARD and JOHN. Rob also talks to Jann about how they are handling the allegations.

"The whole thing is very sad. But the family's great, the boys are great. They are affected by it, but they're moving through it. My boys understand that being a celebrity sometimes exposes you to some really bad stuff and sometimes you get a VIP tour of Disneyland."

Tune in to tonight's ET for more of Rob's interview with Jann Carl.